please help pc wont turn on

last september i built my own computer and it has worked until now. Recently my computer would not turn off even when i commanded it to, so i have had to turn it off manually. today it was working until i was playing a game, fear, and the game froze. i turned off the computer manually and proceeded to turn it back one, and it wouldnt. none of the fans would spin, none of the lights or leds worked, and my router does not indicate thecomputer as connecetd as it usually does when its off. lastly, when my computer was off but working, before this happened, one green indicator light would stay on in the computer, but now it is not. i believe the issue is either the mobo or psu, but i dont know for sure, nor do i know how to test it. please help, i would be grateful!!!!

Hello Little Monkey! <--- Ignore that if you don't understand the reference. Sounds like your PSU is KAPUT! Just borrow a friends PSU if you can and see if that solves the problem. If it doesn't then you need to replace your motherboard.

i decided to go into the old girl now and disconected everything and plugged back in. now the computer will turn on where the fans run on most of the components, but the actual computer wont boot up. everything seems to be working except the leds on my ram are not lighting up. possible problems?

Same problem different symptom. I still think the PSU is at fault. You can take out your memory and try booting your computer. If your motherboard is still working correctly you should get some beep codes that indicated you don't have any memory installed, but if your power supply is truely broken then you can't rely on what your motherboard tells you because who knows what will still run correctly if the voltage/amperage isn't correct.